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Ruby On Rails in UA/Code Review, теоретические вопросы/Сборник рецептов для String

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2008-06-10 09:23:42	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Сборник рецептов для String
	#инициализация строки string = 'My first string' #--- => "My first string" #--- string = 'My first string' # => "My first string" #---Длинна строки string.length # => 15 #--- string.length() # => 15 #--- подсчет колличества символов в строке string.count 'i' # => 2 # "i" occurs twice. string.count('i') # => 2 #--- string.length.next # => 16 #--- french_string = "il \xc3\xa9tait une fois" # => "il \303\251tait une fois" #--- french_string.length # => 18 #--- puts "This string\ncontains a newline" # This string # contains a newline #--- puts 'it may look like this string contains a newline\nbut it doesn\'t' # it may look like this string contains a newline\nbut it doesn't puts 'Here is a backslash: \\ ' # Here is a backslash: \ #--- инициализация многострочной переменной long_string = <<EOF Here is a long string With many paragraphs EOF # => "Here is a long string\nWith many paragraphs\n" puts long_string # Here is a long string # With many paragraphs #--- срезы части строки string # => "My first string" string.slice(3, 5) # => "first" #--- string[3].chr + string[4].chr + string[5].chr + string[6].chr + string[7].chr # => "first" #--- string[3, 5] # => "first" #--- приведение к верхнему регистру string.upcase # => "MY FIRST STRING" string # => "My first string" # приведение к вернему регистру с изменением переменной string.upcase! # => "MY FIRST STRING" string # => "MY FIRST STRING" #--- string.empty? # => false string.include? 'MY' # => true #--- ------------ Занимаюсь вебом и продвижением сайтов.
	Introduction, Ruby Cookbook Source, strilg lenght, string count, Strings, upcase, сборник рецептов

2008-06-08 14:57:37	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Построение строк с частей
	hash = { "key1" => "val1", "key2" => "val2" } string = "" hash.each { \|k,v\| string << "#{k} is #{v}\n" } puts string # key1 is val1 # key2 is val2 #--- string = "" hash.each { \|k,v\| string << k << " is " << v << "\n" } #--- puts hash.keys.join("\n") + "\n" # key1 # key2 #--- data = ['1', '2', '3'] s = '' data.each { \|x\| s << x << ' and a '} s # => "1 and a 2 and a 3 and a " data.join(' and a ') # => "1 and a 2 and a 3" #--- s = "" data.each_with_index { \|x, i\| s << x; s << "\|" if i < data.length-1 } s # => "1\|2\|3" #--- ------------ Занимаюсь вебом и продвижением сайтов.
	each, each_with_index, hash, join, keys, string

2008-06-09 16:28:46	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Замена чайтей текста, вставка переменных в строки
	number = 5 "The number is #{number}." # => "The number is 5." "The number is #{5}." # => "The number is 5." "The number after #{number} is #{number.next}." # => "The number after 5 is 6." "The number prior to #{number} is #{number-1}." # => "The number prior to 5 is 4." "We're ##{number}!" # => "We're #5!" #--- "#{number}" == '5' # => true #--- %{Here is #{class InstantClass def bar "some text" end end InstantClass.new.bar }.} # => "Here is some text." #--- "I've set x to #{x = 5; x += 1}." # => "I've set x to 6." x # => 6 #--- "\#{foo}" # => "\#{foo}" '#{foo}' # => "\#{foo}" #--- name = "Mr. Lorum" email = <<END Dear #{name}, Unfortunately we cannot process your insurance claim at this time. This is because we are a bakery, not an insurance company. Signed, Nil, Null, and None Bakers to Her Majesty the Singleton END #--- <<end_of_poem There once was a man from Peru Whose limericks stopped on line two end_of_poem # => "There once was a man from Peru\nWhose limericks stopped on line two\n" #--- ------------ Занимаюсь вебом и продвижением сайтов.
	#{variable}, variables in string

2008-06-10 12:59:30	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Замена переменных в строках ERB
	template = 'Oceania has always been at war with %s.' template % 'Eurasia' # => "Oceania has always been at war with Eurasia." template % 'Eastasia' # => "Oceania has always been at war with Eastasia." 'To 2 decimal places: %.2f' % Math::PI # => "To 2 decimal places: 3.14" 'Zero-padded: %.5d' % Math::PI # => "Zero-padded: 00003" #--- require 'erb' template = ERB.new %q{Chunky <%= food %>!} food = "bacon" template.result(binding) # => "Chunky bacon!" food = "peanut butter" template.result(binding) # => "Chunky peanut butter!" #--- puts template.result # Chunky peanut butter! #--- template = %q{ <% if problems.empty? %> Looks like your code is clean! <% else %> I found the following possible problems with your code: <% problems.each do \|problem, line\| %> * <%= problem %> on line <%= line %> <% end %> <% end %>}.gsub(/^\s+/, '') template = ERB.new(template, nil, '<>') problems = [["Use of is_a? instead of duck typing", 23], ["eval() is usually dangerous", 44]] template.run(binding) # I found the following possible problems with your code: # * Use of is_a? instead of duck typing on line 23 # * eval() is usually dangerous on line 44 problems = [] template.run(binding) # Looks like your code is clean! #--- class String def substitute(binding=TOPLEVEL_BINDING) eval(%{"#{self}"}, binding) end end template = %q{Chunky #{food}!} # => "Chunky \#{food}!" food = 'bacon' template.substitute(binding) # => "Chunky bacon!" food = 'peanut butter' template.substitute(binding) # => "Chunky peanut butter!" #--- food = '#{system("dir")}' puts template.substitute(binding) # Chunky #{system("dir")}! #--- ------------ Занимаюсь вебом и продвижением сайтов.
	ERB, erb.result, substitute

2008-06-08 14:29:56	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Обратное преобразование String
	s = ".sdrawkcab si gnirts sihT" s.reverse # => "This string is backwards." s # => ".sdrawkcab si gnirts sihT" s.reverse! # => "This string is backwards." s # => "This string is backwards." #--- s = "order. wrong the in are words These" s.split(/(\s+)/).reverse!.join('') # => "These words are in the wrong order." s.split(/\b/).reverse!.join('') # => "These words are in the wrong. order" #--- "Three little words".split(/\s+/) # => ["Three", "little", "words"] "Three little words".split(/(\s+)/) # => ["Three", " ", "little", " ", "words"] #--- ------------ Занимаюсь вебом и продвижением сайтов.
	join, split, string.reverse

2008-06-10 06:58:20	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Изменение представления непечатаемых символов
	octal = "\000\001\010\020" octal.each_byte { \|x\| puts x } # 0 # 1 # 8 # 16 hexadecimal = "\x00\x01\x10\x20" hexadecimal.each_byte { \|x\| puts x } # 0 # 1 # 16 # 32 #--- open('smiley.html', 'wb') do \|f\| f << '<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">' f << "\xe2\x98\xBA" end #--- "\a" == "\x07" # => true #ASCII 0x07 = BEL (Sound system bell) "\b" == "\x08" # => true #ASCII 0x08 = BS (Backspace) "\e" == "\x1b" # => true #ASCII 0x1B = ESC (Escape) "\f" == "\x0c" # => true #ASCII 0x0C = FF (Form feed) "\n" == "\x0a" # => true #ASCII 0x0A = LF (Newline/line feed) "\r" == "\x0d" # => true #ASCII 0x0D = CR (Carriage return) "\t" == "\x09" # => true #ASCII 0x09 = HT (Tab/horizontal tab) "\v" == "\x0b" # => true #ASCII 0x0B = VT (Vertical tab) #--- "\x10\x11\xfe\xff" # => "\020\021\376\377" "\x48\145\x6c\x6c\157\x0a" # => "Hello\n" #--- "\\".size # => 1 "\\" == "\x5c" # => true "\\n"[0] == ?\\ # => true "\\n"[1] == ?n # => true "\\n" =~ /\n/ # => nil #--- "\C-a\C-b\C-c" # => "\001\002\003" "\M-a\M-b\M-c" # => "\341\342\343" #--- ?\C-a # => 1 ?\M-z # => 250 contains_control_chars = /[\C-a-\C-^]/ 'Foobar' =~ contains_control_chars # => nil "Foo\C-zbar" =~ contains_control_chars # => 3 contains_upper_chars = /[\x80-\xff]/ 'Foobar' =~ contains_upper_chars # => nil "Foo\212bar" =~ contains_upper_chars # => 3 #--- def snoop_on_keylog(input) input.each_byte do \|b\| case b when ?\C-c; puts 'Control-C: stopped a process?' when ?\C-z; puts 'Control-Z: suspended a process?' when ?\n; puts 'Newline.' when ?\M-x; puts 'Meta-x: using Emacs?' end end end snoop_on_keylog("ls -ltR\003emacsHello\012\370rot13-other-window\012\032") # Control-C: stopped a process? # Newline. # Meta-x: using Emacs? # Newline. # Control-Z: suspended a process? #--- puts "foo\tbar" # foo bar puts %{foo\tbar} # foo bar puts %Q{foo\tbar} # foo bar puts 'foo\tbar' # foo\tbar puts %q{foo\tbar} # foo\tbar #--- ------------ Занимаюсь вебом и продвижением сайтов.
	each_byte, string, unprinting chars

2008-06-06 06:12:51	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Конвертация иежду чарсетами и переменными
	?a # => 97 ?! # => 33 ?\n # => 10 'a'[0] # => 97 'bad sound'[1] # => 97 #--- 97.chr # => "a" 33.chr # => "!" 10.chr # => "\n" 0.chr # => "\000" 256.chr # RangeError: 256 out of char range #--- ------------ Занимаюсь вебом и продвижением сайтов.
	string ?, string chr

2008-06-10 13:17:50	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Конвертация между строками и символами
	:a_symbol.to_s # => "a_symbol" :AnotherSymbol.id2name # => "AnotherSymbol" :"Yet another symbol!".to_s # => "Yet another symbol!" #--- :dodecahedron.object_id # => 4565262 symbol_name = "dodecahedron" symbol_name.intern # => :dodecahedron symbol_name.intern.object_id # => 4565262 #--- "string".object_id # => 1503030 "string".object_id # => 1500330 :symbol.object_id # => 4569358 :symbol.object_id # => 4569358 #--- "string1" == "string2" # => false :symbol1 == :symbol2 # => false #--- ------------ Занимаюсь вебом и продвижением сайтов.
	.id2name, intern, intern.object_id, object_id

2008-06-09 20:46:35	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Обработка строк посимвольно
	'foobar'.each_byte { \|x\| puts "#{x} = #{x.chr}" } # 102 = f # 111 = o # 111 = o # 98 = b # 97 = a # 114 = r #--- 'foobar'.scan( /./ ) { \|c\| puts c } # f # o # o # b # a # r #--- "foo\nbar".each { \|x\| puts x } # foo # bar #--- french = "\xc3\xa7a va" #--- french.scan(/./) { \|c\| puts c } # � # � # a # # v # a french.scan(/./u) { \|c\| puts c } # ç # a # # v # a $KCODE = 'u' french.scan(/./) { \|c\| puts c } # ç # a # # v ------------ Занимаюсь вебом и продвижением сайтов.
	each_byte, scan

2008-06-09 17:24:14	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Обработка строк с разбивкой по словам
	class String def word_count frequencies = Hash.new(0) downcase.scan(/\w+/) { \|word\| frequencies[word] += 1 } return frequencies end end %{Dogs dogs dog dog dogs.}.word_count # => {"dogs"=>3, "dog"=>2} %{"I have no shame," I said.}.word_count # => {"no"=>1, "shame"=>1, "have"=>1, "said"=>1, "i"=>2} #--- # похоже на /\w+/, только не учитывает слова с подчеркиванием. /[0-9A-Za-z]/ # Все что угодно кроме пробелов это слова. /[^\S]+/ #Учитывет тире и апостроф как части слова. /[-'\w]+/ # Хорошее эвристические сравнения для слов. /(\w+([-'.]\w+)/ #--- class String def word_count frequencies = Hash.new(0) downcase.scan(/(\w+([-'.]\w+))/) { \|word, ignore\| frequencies[word] += 1 } return frequencies end end %{"That F.B.I. fella--he's quite the man-about-town."}.word_count # => {"quite"=>1, "f.b.i"=>1, "the"=>1, "fella"=>1, "that"=>1, # "man-about-town"=>1, "he's"=>1} #--- french = "il \xc3\xa9tait une fois" french.word_count # => {"fois"=>1, "une"=>1, "tait"=>1, "il"=>1} #--- $KCODE='u' french.word_count # => {"fois"=>1, "une"=>1, "�tait"=>1, "il"=>1} #--- ------------ Занимаюсь вебом и продвижением сайтов.
	words count, подсчет слов в тексте, Разбитие текста по словам

2008-06-08 04:33:13	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Изменение регистра строк
	s = 'HELLO, I am not here. I WENT to tHe MaRKEt.' s.upcase # => "HELLO, I AM NOT HERE. I WENT TO THE MARKET." s.downcase # => "hello, i am not here. i went to the market." s.swapcase # => "hello, i AM NOT HERE. i went TO ThE mArkeT." s.capitalize # => "Hello, i am not here. i went to the market." #--- un_banged = 'Hello world.' un_banged.upcase # => "HELLO WORLD." un_banged # => "Hello world." banged = 'Hello world.' banged.upcase! # => "HELLO WORLD." banged # => "HELLO WORLD." #--- class String def capitalize_first_letter self[0].chr.capitalize + self[1, size] end def capitalize_first_letter! unless self[0] == (c = self[0,1].upcase[0]) self[0] = c self end # Return nil if no change was made, like upcase! et al. end end s = 'i told Alice. She remembers now.' s.capitalize_first_letter # => "I told Alice. She remembers now." s # => "i told Alice. She remembers now." s.capitalize_first_letter! s # => "I told Alice. She remembers now." #--- 'LOWERCASE ALL VOWELS'.tr('AEIOU', 'aeiou') # => "LoWeRCaSe aLL VoWeLS" 'Swap case of ALL VOWELS'.tr('AEIOUaeiou', 'aeiouAEIOU') # => "SwAp cAsE Of aLL VoWeLS" #--- ------------ Занимаюсь вебом и продвижением сайтов.
	string capitalize, string downcase, string swapcase, string upcase

2008-06-08 14:46:55	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Управление пробелами
	" \tWhitespace at beginning and end. \t\n\n".strip # => "Whitespace at beginning and end." #--- s = "Some text." s.center(15) # => " Some text. " s.ljust(15) # => "Some text. " s.rjust(15) # => " Some text." #--- #Normalize Ruby source code by replacing tabs with spaces ruby_ode.gsub("\t", " ") #Transform Windows-style newlines to Unix-style newlines "Line one\n\rLine two\n\r".gsub("\n\r", "\n") # => "Line one\nLine two\n" #Transform all runs of whitespace into a single space character "\n\rThis string\t\t\tuses\n all\tsorts\nof whitespace.".gsub(/\s+/, " ") # => " This string uses all sorts of whitespace." #--- " \bIt's whitespace, Jim,\vbut not as we know it.\n".gsub(/[\s\b\v]+/, " ") # => " It's whitespace, Jim, but not as we know it. " #--- s = " Whitespace madness! " s.lstrip # => "Whitespace madness! " s.rstrip # => " Whitespace madness!" #--- "four".center(5) # => "four " "four".center(6) # => " four " #--- ------------ Занимаюсь вебом и продвижением сайтов.
	center, edit whitespace, ljust, rjust, whitespace

2008-06-09 03:57:50	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Тестирование типа на объект или строку
	'A string'.respond_to? :to_str # => true Exception.new.respond_to? :to_str # => true 4.respond_to? :to_str # => false #--- def join_to_successor(s) raise ArgumentError, 'No successor method!' unless s.respond_to? :succ return "#{s}#{s.succ}" end join_to_successor('a') # => "ab" join_to_successor(4) # => "45" join_to_successor(4.01) # ArgumentError: No successor method! #--- ------------ Занимаюсь вебом и продвижением сайтов.
	check Object, check String, respond_to?

2008-06-10 06:13:38	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Вырезание различный частей текста
	s = 'My kingdom for a string!' s.slice(3,7) # => "kingdom" s[3,7] # => "kingdom" s[0,3] # => "My " s[11, 5] # => "for a" s[11, 17] # => "for a string!" #--- s[/.ing/] # => "king" s[/str.*/] # => "string!" #--- s.slice(3) # => 107 s[3] # => 107 107.chr # => "k" s.slice(3,1) # => "k" s[3,1] # => "k" #--- s.slice(-7,3) # => "str" s[-7,6] # => "string" #--- s[15...s.] # => "a string!" #--- ------------ Занимаюсь вебом и продвижением сайтов.
	chr, length, slice

2008-06-10 12:21:57	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Обработка международных кодировок
	$KCODE='u' require 'jcode' #--- $ ruby -Ku -rjcode #--- #!/usr/bin/ruby -Ku -rjcode #--- string = "\xef\xbc\xa1" + "\xef\xbc\xa2" + "\xef\xbc\xa3" + "\xef\xbc\xa4" + "\xef\xbc\xa5" + "\xef\xbc\xa6" #--- string.size # => 18 string.jsize # => 6 #--- string.count "\xef\xbc\xa2" # => 13 string.jcount "\xef\xbc\xa2" # => 1 #--- "\xef\xbc\xa2".length # => 3 "\xef\xbc\xa2".jlength # => 1 #--- ------------ Занимаюсь вебом и продвижением сайтов.
	jcode, jlength, jsize

2008-06-10 05:21:49	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Разбивка текста на строки с фиксированым размером
	def wrap(s, width=78) s.gsub(/(.{1,#{width}})(\s+\|\Z)/, "\\1\n") end wrap("This text is too short to be wrapped.") # => "This text is too short to be wrapped.\n" puts wrap("This text is not too short to be wrapped.", 20) # This text is not too # short to be wrapped. puts wrap("These ten-character columns are stifling my creativity!", 10) # These # ten-character # columns # are # stifling # my # creativity! #--- poetry = %q{It is an ancient Mariner, And he stoppeth one of three. "By thy long beard and glittering eye, Now wherefore stopp'st thou me?} puts wrap(poetry, 20) # It is an ancient # Mariner, # And he stoppeth one # of three. # "By thy long beard # and glittering eye, # Now wherefore # stopp'st thou me? #--- prose = %q{I find myself alone these days, more often than not, watching the rain run down nearby windows. How long has it been raining? The newspapers now print the total, but no one reads them anymore.} puts wrap(prose, 60) # I find myself alone these days, more often than not, # watching the rain run down nearby windows. How long has it # been # raining? The newspapers now print the total, but no one # reads them # anymore. #--- def reformat_wrapped(s, width=78) s.gsub(/\s+/, " ").gsub(/(.{1,#{width}})( \|\Z)/, "\\1\n") end #--- def reformat_wrapped(s, width=78) lines = [] line = "" s.split(/\s+/).each do \|word\| if line.size + word.size >= width lines << line line = word elsif line.empty? line = word else line << " " << word end end lines << line if line return lines.join "\n" end puts reformat_wrapped(prose, 60) # I find myself alone these days, more often than not, # watching the rain run down nearby windows. How long has it # been raining? The newspapers now print the total, but no one # reads them anymore. #--- ------------ Занимаюсь вебом и продвижением сайтов.
	word wrap

2008-06-09 23:49:29	Ответить
Ruslan Voloshin Адрес: odessa Сообщений: 1293 Регистр: 2007-03-13 его блог 40 сообщ.	Увеливаем значение каждого элемента строки
	('aa'..'ag').each { \|x\| puts x } # aa # ab # ac # ad # ae # af # ag #--- def endless_string_succession(start) while true yield start start = start.succ end end #--- endless_string_succession('fol') do \|x\| puts x break if x[-1] == x[-2] end # fol # fom # fon # foo #--- '89999'.succ # => "90000" 'nzzzz'.succ # => "oaaaa" #--- 'Zzz'.succ # => "AAaa" #--- 'z'.succ # => "aa" 'aa'.succ # => "ab" 'zz'.succ # => "aaa" #--- 'AA'.succ # => "AB" 'AZ'.succ # => "BA" 'ZZ'.succ # => "AAA" 'aZ'.succ # => "bA" 'Zz'.succ # => "AAa" #--- 'foo19'.succ # => "foo20" 'foo99'.succ # => "fop00" '99'.succ # => "100" '9Z99'.succ # => "10A00" #--- '10-99'.succ # => "11-00" #--- 'a-a'.succ # => "a-b" 'z-z'.succ # => "aa-a" 'Hello!'.succ # => "Hellp!" %q{'zz'}.succ # => "'aaa'" %q{z'zz'}.succ # => "aa'aa'" '$$$$'.succ # => "$$$%" s = '!@-' 13.times { puts s = s.succ } # !@. # !@/ # !@0 # !@1 # !@2 # ... # !@8 # !@9 # !@10 #--- ("a".."e").to_a.reverse_each { \|x\| puts x } # e # d # c # b # a #--- ------------ Занимаюсь вебом и продвижением сайтов.
	succ

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